Vibratory conveyors have been used for decades in various industrial applications. As a general matter, vibratory conveyors include a base frame, and a vibratory conveyor bed which is mounted in spaced relation relative to the base frame, and which further reciprocates in a given pattern in order to move a product, or objects of interest along a given course of travel for further processing.
Depending upon the product being transported, and the environment in which the vibratory conveyor is used, static electricity may build up in either the base frame, or the vibratory conveyor, and which must be dissipated in order to avoid an accidental discharge of the static electricity. It is well known that these electrical discharges of static electricity may cause damage to the vibratory conveyor; electrical devices in the area of the vibratory conveyor, or potentially can ignite combustible materials in the region of the electrical discharge.
To electrically couple the movable vibratory conveyor bed with the underlying base frame so as to provide an electrical pathway for discharging a static electricity charge, various methodologies have been used in the past. For example, this electrical coupling has, heretofore, been achieved by a stainless steel braided cable which had crimped end connections which allowed the stainless steel cable or strap to be secured to the vibratory conveyor, and to the underlying base frame. In this regard this stainless steel braided cable typically was electrically connected by way of the fasteners which had been employed to secure a plurality of supporting, flexible leaf springs to the base frame, and conveyor bed. These flexible leaf springs supported the movement of the vibratory conveyor in spaced relation relative to the base frame.
While this solution worked with some degree of success, the attachment of the metal braided cable in this fashion created a continuous bending at a given location in the cable. This subsequent and repeated bending led to a failure of the cable near the crimped connection which had been formed. Therefore, periodic maintenance was required to replace these braided cables to prevent an accidental discharge of accumulated static electricity.
Other designs have been implemented to try and mitigate the failure which was attendant to the repeated movement of the cable by the reciprocal motion of the conveyor bed. One possible solution was to provide, a rolling-flex braided cable. However, the problem associated with using a rolling-flex cable to mitigate a bending failure was that such a rolling-flex cable required a rather large radius to achieve any measurable benefit. This large radius interfered with other assemblies mounted on the vibratory conveyor and therefore only provided minimal benefit.
In another attempt to try and solve the underlying problem discussed above, sheet metal straps were used, and which were fabricated in a manner so as to allow the stainless steel straps to be secured in the same manner as the earlier employed steel braided cable, to the leaf springs which support the vibratory conveyor bed. Again, this metal strap was still subjected to the same vibratory force experienced by the conveyor bed, and consequently a bending failure occurred in the stainless steel strap at the point where the metal strap was secured by fasteners to the conveyor bed. Further, a rolling configuration made from a strap of stainless steel was attempted. In this rolling-flex configuration the problems associated with the cable remained, that being, that the rather large radius required to achieve measurable benefit, and the subsequent interference with the adjacent spring assemblies used to support the conveyor bed achieved little or no measurable benefit. It was discovered that compromises made to the radiuses which were employed, resulted in premature failures that had only a slightly longer lifetime as compared to that experienced with the bending failure mode as seen with the earlier employed stainless steel braided cables.
In view of these problems, manufacturers of vibratory conveyors have continued to seek an effective means whereby a movable object, such as a vibratory conveyor, can be effectively, electrically coupled to an underlying base frame in a manner which provides effective dissipation of accumulated static electricity in a manner which avoids the shortcomings attendant with the prior art practices that were utilized heretofore. An electrical grounding arm is the subject matter of the present invention.